Recently, as part of environmental measures, low noise pneumatic tires have been required in the market. To meet the requirement, for example, Unexamined Japanese Patent Application Publication No. 2001-113902 discloses such a technology that, as noise reduction interior members, protrusion members are disposed on a rim at predetermined intervals in the circumferential direction of a tire to vary the cross-sectional area of a cavity surrounded by the rim and pneumatic tire in the tire circumferential direction.
One type of noise generated by pneumatic tires is caused by resonance of the air in the cavity of the pneumatic tire during travel. As described above, by varying the cross-sectional area of the cavity in the tire circumferential direction, the frequency of the air resonance is varied to thereby reduce road noise due to the air resonance.
However, if the noise reduction interior members disposed on the rim in the tire as mentioned above are fixed to the rim in advance, assembly of the tire on the rim is obstructed. Therefore, the noise reduction interior member must be installed after one bead of the tire has been placed on the rim. This is difficult because the operator must insert his hands into the narrow space between the rim and tire. As such, attachment of the noise reduction member is difficult and inconvenient.